RE: 15" Tires on 390mm Wheels...just over 2% too small

["KOHLBRENNER,MICHAEL (A-Andover,ex1)" <michael_kohlbrenner@xxxxxxxxxxx>]

From: torresk@domain.elided

> 390mm=15.3544" making them 2.37% too large, no?  My question
> is has anyone experimented with turning the TRX wheels down
> to 15"?  I have access to CNC machines that could easily
> do the job.  Anyone?

Quite frankly, I think this is a crazy idea.

First, you'd be removing almost 3/16" of material off the
radius of the alloys.  I would have to guess that this is
somewhere between 1/4 to 1/2 of the total thickness of the
material at this point.  I wouldn't want to be anywhere near
a car with these wheels mounted...

Second, one of the big reasons that the TRX "system" uses
these oddball diameters is that they use a different
bead and beadseat profile.  They are not compatible with
the standard bead profile, so using oddball diameters
is a way to eliminate the possibility of improper mix
and match.

What this second point means is that even assuming you
knew what the standard bead profile is, you may not have 
enough material to work with to recreate it.

In short, I wouldn't do it.  You can get nice enough
15 x 7 alloys for as little as $500 a set.  Alternatively,
you can find real BMW wheels used for much less than that.
For something that is so important to safety, why screw
around?

Regards,
Mike Kohlbrenner

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